(19)
(11) EP 0 676 132 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
10.04.1996 Bulletin 1996/15

(43) Date of publication A2:
11.10.1995 Bulletin 1995/41

(21) Application number: 95201870.3

(22) Date of filing: 03.05.1988
(51) International Patent Classification (IPC)6: A01F 29/20
(84) Designated Contracting States:
DE FR GB

(30) Priority: 05.05.1987 US 46011

(62) Application number of the earlier application in accordance with Art. 76 EPC:
88303989.3 / 0291216

(71) Applicant: NEW HOLLAND BELGIUM N.V.
B-8210 Zedelgem (BE)

(72) Inventors:
  • McClure, John R.
    Pennsylvania 17557 (US)
  • Strosser, Richard P.
    Akron, Pennsylvania 17501 (US)
  • Chow, Mark K.
    Leola, Pennsylvania 17540 (US)
  • Weaver, Marvin G., Jr.
    Lititz, Pennsylvania 17543 (US)
  • Bohman, Carl E.
    New Holland, Pennsylvania 17557 (US)

(74) Representative: Vandenbroucke, Alberic et al
New Holland Belgium NV. Patent Department Leon Claeysstraat, 3A
B-8210 Zedelgem
B-8210 Zedelgem (BE)


(56) References cited: : 
   
     
    Remarks:
    This application was filed on 07 - 07 - 1995 as a divisional application to the application mentioned under INID code 60.
     


    (54) Method and apparatus for adjusting a shear bar in a forage harvester


    (57) Under the control of a microprocessor (200), first and second motors (110, 112) drive first and second ends (A, B) of a shear bar (102) for adjusting the position of the shear bar (102) relative to a cutter head (100). A knock sensor (118) is provided for sensing impacts between the cutter head (100) and the shear bar (102); the knock sensor output signal being converted to a digital value for controlling the adjusting sequence. Automatic adjustment of the shear bar (102) relative to the cutter head (100) involves movement of the shear bar (102) towards the cutter head (100) through a plurality of incremental steps until the shear bar (102) contacts the cutter head (100) and whereafter the shear bar (102) is backed off through a predetermined number of incremental steps.
    A knocker (122) may be provided for inducing vibrations in the shear bar (102) to thereby test the operability of the knock sensor (118) and its output circuitry. The sensitivity of the adjustment system to the output of the knock sensor (118) is set automatically before an adjustment sequence begins to account for variations in the knock sensor (118), its output circuitry, and "noise" vibrations induced in the shear bar (102) by normal machine operation.






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